A sealed power tool

Abstract

Disclosed herein is a sealed power tool comprising a housing section having a sealed compartment, the sealed compartment to house a motor and a Programmable Control Board Assembly(s) (PCB A) to control operation of the motor, an air passage defined in the housing section facilitating in the flow of air and a handle section with a battery pack coupled with the housing section. Further, the sealed compartment isolates and provides a seal for the motor, the torque transducer, the planetary gear stage, and the PCB A in the housing section, a fan facilitates air flow along the air passage in the housing section to dissipate heat and the battery pack in the handle section powers the motor, the fan and the PCBA in the housing section.

Description

A SEALED POWER TOOLTECHNICAL FIELD

[0001] The disclosed invention pertains generally to a power tool. More particularly, embodiments of the disclosed invention provide a sealed handheld battery-operated power tool.Background Art

[0002] Generally, power or torque tools that are rated for operation in dirty / wet and hazardous environments are limited to hydraulically powered or pneumatically powered. For a compact, portable, handheld battery-operated power or torque tools, operating it in the dirty / wet or hazardous environments poses threat of fire hazards. There is always a possibility for detachment of battery from the handheld device which may cause a spark leading to a fire accident. This possibility restricts the use of handheld battery-operated power tools in wet and hazardous environments. Also, heat dissipation needs to be streamlined in the power tool so as to maintain the operating temperatures allowing the use of the power tool in all environmental conditions.

[0003] This disclosure teaches a battery-operated handheld power tool that can be operated in all working conditions.

[0004] Thus, in light of the above-stated discussion, there is an urgent need for a technical solution that overcomes the above-stated limitations. The present disclosure focuses on a sealed handheld battery-operated power tool.SUMMARY OF THE DISCLOSURE[ooos] The following is a summary description of illustrative embodiments of the invention. It is provided as a preface to assist those skilled in the art to more rapidly assimilate thedetailed design discussion which ensues and is not intended in any way to limit the scope of the claims which are appended hereto in order to particularly point out the invention.

[0006] According to illustrative embodiments, the present disclosure focuses on a sealed power tool which overcome the above mentioned disadvantages or provide the users with a useful or commercial choice.

[0007] According to the present disclosure, a sealed power tool is disclosed herein. The power tool comprising a housing section having a sealed compartment, the sealed compartment to house a motor, a torque transducer, a planetary gear stage and two Printed Circuit Board Assemblies (PCBAs), namely a Motor Drive / Control Board (MDCB) to control operation of the motor and a Base Service Module (BSM) for data storage and Communications, an air passage defined in the housing section facilitating in the flow of air and a handle section with a battery pack coupled with the housing section. Further, the sealed compartment isolates provides a seal for the motor and the PCBAs, a fan facilitates air flow along the air passage in the housing section to dissipate heat and the battery pack in the handle section powers the motor, the fan and the PCBAs in the housing section.

[0008] The housing section further includes a bearing housing, a motor flange and a fan shroud.

[0009] In one embodiment of the present invention, the bearing housing is provided at a front end of the housing section and the fan shroud is provided at a rear end of the housing section, the fan shroud provides a protective cover for the fan.[ooio] In one embodiment of the present invention, the motor is sealed and isolated inside the sealed compartment by slip fit or press fit mechanism with a thermally conductive adhesive. A motor flange is provided inside the sealed compartment in the housing section and coupled with the motor, the motor is operated to apply drive torque and rotate the planetary gear stage. The output spindle of the planetary gear stage transits the sealed compartment via a environmental seal to apply torque to the gearbox 116, which rotates a spindle 118 to apply torque for fastening lug nuts and bolts.[OOH] In another embodiment of the present invention, a thermal padmay be provided along an inner surface of the sealed compartment, whereby the motor is isolated by the thermal pad inside the sealed compartment. The motor flange further rotates a bearing provided inside the bearing housing in the front end of the housing section. The bearing further rotates a spindle that is attached to the bearing, the spindle is rotated to apply torque for fastening lug nuts and bolts.

[0012] Furthermore, a cylinder seal plate is provided between the sealed compartment and the fan in the rear end of the housing section to act as a sealing barrier.

[0013] In one embodiment of the present invention, the motor flange, the motor, the torque transducer, the planetary gear stage, the fan, the bearing housing and the fan shroud are positioned along a same horizontal axis in the housing section.

[0014] Further, an additional PCBA, the User Interface Controller (UIC) is provided in the rear end of the housing section, the UIC controls the operation of the power tool and in an embodiment of the present invention the PCBAs, the MDCB and the BSM, are provided below the motor in the sealed compartment.

[0015] In one embodiment of the present invention, the handle section couples with the sealed compartment in the housing section via sealed electrical terminals. When the handle section is coupled with the sealed compartment, the battery pack is mated with the MDCB and the BSM via sealed electrical terminals establishing an electrical connection to power the PCB, the motor, the fan, the UIC and the BSM.

[0016] In one embodiment of the present invention, the air passage is provided around the sealed compartment along the horizontal axis in the housing section, the air passage extends along the sealed compartment and terminates in the fan shroud. The air passage is provided with an air intake and an air exhaust, the air exhaust is provided in the fan shroud. The fan is operated to suck ambient air into the air passage via the air intake and blow out from the air passage via the air exhaust. The flow of ambient air along the air passage facilitates in dissipating heat generated by the motor and the MDCB in the housing section.

[0017] The present invention introduces a sealed battery-operated handheld power tool that can be used in any type of work environments such as dry / wet and hazardous working conditions. In order to operate in the aforementioned environments, components such as motors and electronics must be protected from the environment as well as prevent from generating a spark or achieving an external temperature which can ignite a hazardous environment. Conventional power tools that are rated for operation in dirty / wet and hazardous environments are limited to hydraulically-powered and pneumatically-powered torque tools. This restricts the usability of portable hand held power tools. This disclosure discloses a sealed power tool that completely isolates the heat generating components such as the motor and electronics from the externalenvironment thus providing a seal against any potential fire hazard. It further provides an improved air circulation in the power tool for better heat dissipation. Because electrically powered devices generate heat that needs to be actively cooled via a fan which draw and exhaust air from / to the surroundings. Therefore, the present disclosure provides a means to isolate these components from the environment, yet allow for removal of heat. Utilization of the power tool described in this disclosure will enable the power tool to be used remotely irrespective of the working environment by isolating the components and providing effective heat dissipation.

[0018] This patent disclosure should be limited by the claim set which covers the foundation for the proposed sealed power tool rather than the small subset of possible embodiments described in the specification.

[0019] These and other advantages will be apparent from the present application of the embodiments described herein.

[0020] The preceding is a simplified summary to provide an understanding of some embodiments of the present invention. This summary is neither an extensive nor exhaustive overview of the present invention and its various embodiments. The summary presents selected concepts of the embodiments of the present invention in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other embodiments of the present invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.BRIEF DESCRIPTION OF DRAWINGS

[0021] To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly describes the accompanying drawingsrequired for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description merely show some embodiments of the present disclosure, and a person of ordinary skill in the art can derive other implementations from these accompanying drawings without creative efforts. All of the embodiments or the implementations shall fall within the protection scope of the present disclosure.

[0022] Fig. 1 (a) depicts an isometric view of preferred embodiment of this invention, according to embodiments of the present invention;

[0023] Fig. 1 (b) depicts a right-side view of preferred embodiment of this invention, according to embodiments of the present invention;

[0024] Fig. 1 (c) depicts a front view of preferred embodiment of this invention, according to embodiments of the present invention;

[0025] Fig. 1 (d) depicts a left-side view of preferred embodiment of this invention, according to embodiments of the present invention;

[0026] Fig. 1 (e) depicts a back view of preferred embodiment of this invention, according to embodiments of the present invention;

[0027] Fig. 2(a) depicts an isometric view of a housing section, according to embodiments of the present invention disclosed herein; and

[0028] Fig. 2(b) depicts a front view of the housing section, according to embodiments of the present invention disclosed herein; and

[0029] Fig. 3 depicts a sectional view of the housing section, according to embodiments of the present invention disclosed herein.

[0030] The sealed power tool is illustrated in the accompanying drawings, which like reference letters indicate corresponding parts in the various figures. It should be noted that the accompanying figure is intended to present illustrations of exemplary embodiments of the present disclosure. This figure is not intended to limit the scope of the present disclosure. It should also be noted that the accompanying figure is not necessarily drawn to scale.DESCRIPTION OF EMBODIMENTS

[0031] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.

[0032] The preferred embodiments of this invention will be disclosed in the following descriptions. While some preferred embodiments are described, the disclosure should be limited by the claim set rather than the preferred embodiments utilized to illustrate some of the potential embodiments that this invention disclosure will make obvious to those skilled in the art.

[0033] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person ofskill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0034] The articles "a", "an" and "the" are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0035] The terms "comprise" and "comprising" are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as "consists of only". Throughout this specification, unless the context requires otherwise the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.

[0036] The term "including" is used to mean "including but not limited to". "Including" and "including but not limited to" are used interchangeably.

[0037] FIGS. 1 (a) depicts an isometric view of preferred embodiment of this invention, according to embodiments of the present invention. A power tool 1000 is a mechanized torque wrench used to apply to torque to fasten or loosen different components such as a nut, bolt, or lag screw. The power tool 1000 may be hydraulically driven or pneumatically driven based on the requirements. According to preferred embodiments of the present invention, the power tool 1000 is a battery-operated hand-held portable power tool 1000. It may be understood that the power tool 1000 is operated by an onboard power source in the power tool 1000 such as a battery pack 110 rather than an external power source such as a pneumatic or hydraulic power source.

[0038] In an embodiment of the present invention, the power tool 1000 may include a housing section 102 and a handle section 104. The housing section 102 is provided with a sealed compartment 106 and an air passage and the handle section 104 has provisions to attach a removable battery pack 110. The sealed compartment 106 is a separate, defined hollow space inside the housing section 102. The sealed compartment 106 is assigned with specific components to be sealed and isolated. According to preferred embodiments of the present invention, a motor, a torque transducer, a planetary gear stage two Printed Circuit Board Assemblies (PCBAs), namely a Motor Drive Control Board (MDCB) and a Base Control Module (BSM), are isolated and sealed inside the sealed compartment 106 in the housing section 102. Further, the sealed compartment 106 is isolated from the handle section 104 providing the seal for the motor, the torque transducer, the planetary gear stage, the PCBAs, and / or other electronics to prevent against heat induced fire hazard and electrical spark. Further, the air passage in the defined along an outer surface of the housing section 102 to facilitate air flow and dissipate heat in the power tool 1000.It may be understood that apart from the sealed compartment 106, the housing section 102 may include without any limitation various components as required for the functioning of the power tool 1000. Further, the motor, the torque transducer, the planetary gear stage and the PCBAs are sealed off in the sealed compartment 106 except for their mechanical and electrical connections with other components.

[0039] Fig. 1 (b) depicts a right-side view of preferred embodiment of this invention, according to embodiments of the present invention. According to the preferred embodiments, the housing section 102 includes a bearing housing 112, a motor, a torquetransducer, a planetary gear stage, flange, a fan, a fan shroud 124 and a User Interface Controller (UIC) 108 (unnumbered components not showed in the Figures). The power tool 1000 is provided with a front end 120 and a rear end 122. The front end 120 of the power tool 1000 is where drive torque is applied to perform fastening or loosening operation and the rear end 122 represents the Man Machine Interface (MMI) of the power tool 1000. In an embodiment of the present invention, the bearing housing 112 is provided at the front end 120 of the housing section 102 and the fan shroud 124 is provided at a rear end 122 of the housing section 102. The bearing housing 112 houses an output spindle of the planetary gear stage that rotates with the motor and the fan shroud 124 provides a protective cover to the fan. The fan is positioned opposite to the bearing housing 112 in the housing section 102. In an embodiment of the present invention, the UIC 108 is provided at the rear end 122 of the housing section 102 and controls the operation of the power tool 1000. Further, the sealed compartment 106 is isolated from the handle section 104 having the removable battery pack 110. It may be understood that apart from the sealed compartment 106, the housing section 102 may include without any limitation various components as required for the functioning of the power tool 1000. Further, the motor and the PCBAs (MDCB and BSM) are sealed off in the sealed compartment 106 except for their mechanical and electrical connections with other components.

[0040] Fig. 1 (c) depicts a front view of preferred embodiment of this invention, according to embodiments of the present invention. In an embodiment of the present invention, the handle section 104 is coupled with the housing section 102 by means of fastening screw mechanism. According to the preferred embodiments, the housing section 102 issubstantially cylindrical in shape. The handle section 104 is provided with a coupling end and a distal end. The coupling end of the handle section 104 is coupled with the housing section 102. When coupled, the handle section 104 extends vertically downwards perpendicular to a horizontal axis of the housing section 102. The handle section 104 further includes a handle with a trigger and the removable battery pack 110. The handle section 104 couples closer to the axis of the housing section 102 providing better ergonomics and stability during the use of the power tool 1000. Further, the trigger in the handle section 104 is adapted to operate the motor and cause rotation either in clockwise and counter-clockwise direction. Furthermore, the removable battery pack 110 is provided at the distal end of the handle section 104. This position of the battery pack 110 provides for an even weight distribution in the power tool 1000. In an embodiment of the present invention the battery pack 110 is a rechargeable battery.

[0041] Fig. 1 (d) depicts a left-side view of preferred embodiment of this invention, according to embodiments of the present invention. According to preferred embodiments of the present invention, the motor, the torque transducer, the planetary gear stage, the PCBAs (MDCB and BSM) are isolated and sealed inside the sealed compartment 106 in the housing section 102. Further, the air passage is defined in the outer surface of the housing section 102. The air passage extends along the horizontal axis in the housing section 102 starting behind the bearing housing 112 and terminating in the fan shroud 124. The air passage is the active cooling available in the power tool 1000 to dissipate the heat generated during its operation. Since, the motor and the MDCB are isolated inside the sealed cavity, it is imperative to actively cool the motor to prevent it from overheating. As the air passage is defined around the first cavity 106 in the housingsection 102, the passage of ambient air provides for an effective heat dissipation. Further, the air passage is provided with an air intake 112 and an air exhaust 114, the air exhaust 114 is provided in the fan shroud 124. The ambient air enters through the air passage via the air intake 114 and exits via the air exhaust 124.

[0042] Fig. 1 (e) depicts a back view of preferred embodiment of this invention, according to embodiments of the present invention. In an embodiment of the present invention, the MDCB and the BSM is provided below the motor in the sealed compartment 106. Further, the MDCB may include means to connect the motor to the electrical power supply, and may also include overload protection for the motor, and over-current protection for the motor and wiring. The BSM is responsible for data storage and communication (and / or controlling various electronic components)-in the power tool 1000. It may be apparent to a person of ordinary skill in the art that the working of the MDCB and the BSM is already known and has not been explained in detail to maintain brevity of the specification.

[0043] Fig. 2(a) depicts an isometric view of a housing section, according to embodiments of the present invention. Fig. 2(b) depicts a front view of the housing section, according to embodiments of the present invention. For the sake of brevity figs 2(a) and 2(b) are described together. The isolation and the sealing inside the sealed compartment 106 provides protection for the motor, the torque transducer, the planetary gear stage, two of the PCBAs and / or other electronics to prevent against heat induced fire hazard and electrical spark. During, operation of the power tool 1000, there is always a possibility for detachment of the battery pack 110 from the handle section 104. This detachment may cause a spark and a cause for fire hazard. The motor and the PCBAs are the vulnerable components in the power tool 1000 since the motor and MDCB are in hotcondition. The sealed isolation of both the motor and the MDCB eliminates this risk by completely severing the said components from any outside exposure. It may be understood that apart from the sealed compartment 106, the housing section 102 may include without any limitation various components as required for the functioning of the power tool 1000. Further, the motor and the PCBA are sealed off in the sealed compartment 106 except for their mechanical and electrical connections with other components.

[0044] FIG. 3 depicts a sectional view of the housing section, according to embodiments of the present invention disclosed herein. In an embodiment of the present invention, the motor 300 is sealed and isolated inside the sealed compartment 106 by slip fit or press fit mechanism with a thermally conductive adhesive. The thermally conductive adhesive holds the motor 300 in position inside the sealed compartment 106 of the housing section 102. Furthermore, the motor flange 310 is provided inside the sealed compartment 106 in the housing section 102 and coupled with the motor 300. The motor 300 is operated to apply drive torque and rotate the planetary gear stage which in turn rotates the planetary gear spindle (not shown) which applies torque to a gearbox 116 which drives a spindle 118 that is attached to the gearbox 116. The spindle 118 is rotated to apply torque for fastening components such as lug nuts, bolts etc. It may be understood that the spindle 118 may also be rotated in opposite direction by the motor 300 to unscrew different mechanical components such as lug nuts, bolts etc. The bearing housing 112 and the spindle 118 are provided at the front end 120 of the housing section 102. Moreover, a cylinder seal plate 308 is provided between the sealed compartment 106 and the fan 302 in the rear end 122 of the housing section 102. The cylinder seal plate308 acts as a sealing barrier between the motor 300 and the fan 302. The motor flange 310, the motor 300, the torque transducer, the planetary gearset, the fan 302, the bearing housing 112 and the fan shroud 124 are positioned along a same horizontal axis in the housing section 102.

[0045] A thermal pad 306 may be provided along an inner surface of the sealed compartment 106. The thermal pad 306 may isolate the motor 300 inside the sealed compartment 106 from heat and thermal variations.

[0046] In an embodiment of the present invention, two of the PCBAs (MDCB and BSM) which control the motor and provide data storage and communication of the power tool 1000, are mounted on the PCBA mount 304 inside the sealed compartment 106. When the handle section 104 is coupled with the housing section 102, the battery pack 110 is electrically mated with the MDCB and the BSM via the sealed electrical terminals establishing an electrical connection to power the motor 300, the fan 302, the UIC and the BSM. The battery pack 110 is the power source that powers different component in the power tool 1000.

[0047] During continuous usage of the power tool 1000, a significant amount of heat is generated by the motor 300 and MDCB. This generated heat needs to be effectively dissipated for effective functioning of the power tool 1000 and prevent from any potential fire hazards. Since, the motor 300 is isolated in the sealed compartment 106, the fan 302 is operated to facilitate flow of ambient air over the first cavity 106 via the air passage. When the fan 302 is operated, the ambient air is sucked into the air passage via the air intake 112 and blown out from the air passage via the air exhaust 114. The flow of ambient air along the air passage facilitates in dissipating heat generated by the motor300 and the MDCB in the housing section 102 and actively cooling the power tool 1000. In an embodiment of the present invention, the sealed power tool 1000 is a hand-held battery-operated power tool 1000 and the fan 302 is a thermostatically controlled electric fan.

[0048] While the invention has been described in connection with what is presently considered to be the most practical and various embodiments, it will be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0049] A person of ordinary skill in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, computer software, or a combination thereof.

[0050] The foregoing descriptions of specific embodiments of the present technology have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present technology and its practical software, to thereby enable others skilled in the art to best utilize the present technology and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstancemay suggest or render expedient, but such are intended to cover the software or implementation without departing from the spirit or scope of the claims of the present technology.

[0051] Disjunctive language such as the phrase “at least one of X, Y, Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.

[0052] In a case that no conflict occurs, the embodiments in the present disclosure and the features in the embodiments may be mutually combined. The foregoing descriptions are merely specific implementations of the present disclosure, but are not intended to limit the protection scope of the present disclosure. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present disclosure shall fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

What is claimed for:1 . A sealed power tool comprising: a housing section having a sealed compartment, the sealed compartment to house a motor, a torque transducer, a planetary gearset and Programmable Control Board Assembly(s) (PCBA); an air passage defined in the housing section facilitating in the flow of air; a handle section with a removable battery pack coupled with the housing section, wherein the sealed compartment isolates and provides a seal for the motor and the PCBA, a fan facilitates air flow along the air passage in the housing section to dissipate heat and the battery pack in the handle section powers the motor, the fan and the PCBA in the housing section.

2. The power tool of claim 1 , wherein the sealed compartment further includes a base Control Module (BSM) and is isolated from the handle section providing the seal for the motor, torque transducer, planetary gear stage the PCBA, and / or other electronics to prevent against heat induced fire hazard and electrical spark.

3. The power tool of claim 1 , wherein the housing section further includes a bearing housing, a motor flange a fan shroud.

4. The power tool of claim 3, wherein the bearing housing is provided at a front end of the housing section and the fan shroud is provided at a rear end of the housing section, the fan shroud provides a protective cover for the fan.

5. The power tool of either claim 1 , 2 or 3, wherein the PCBA includes a Motor Drive Controller (MDCB) to control operation of the motor and a Base Services Module (BSM) for data storage and communication.

6. The power tool of claim 1, wherein the motor is sealed and isolated inside the sealed compartment by slip fit or press fit mechanism with a thermally conductive adhesive.

7. The power tool of claim 1 , wherein a thermal pad is provided along an inner surface of the sealed compartment, the motor is isolated by the thermal pad inside the sealed compartment.

8. The power tool of claim 1, wherein a planetary gear spindle transits the sealed compartment in the housing section and coupled with the motor, applies drive torque to apply torque to the gearbox and rotate the spindle to apply torque for fastening lug nuts and bolts.

9. The power tool of claim 1 , wherein the motor flange further rotates a bearing provided inside the bearing housing in the front end of the housing section.

10. The power tool of claim 1 , wherein the planetary gear spindle is rotated to apply torque for fastening lug nuts and bolts.

11. The power tool of claim 1 , wherein a cylinder seal plate is provided between the sealed compartment and the fan in the rear end of the housing section to act as a sealing barrier.

12. The power tool of claim 1 , wherein the motor flange, the motor, torque transdcuer, planetary gear set, the fan, the bearing housing and the fan shroud are positioned along a same horizontal axis in the housing section.

13. The power tool of claim 1 , wherein the PCBA includes a User Interface Controller (UIC) provided in the rear end of the housing section, the UIC controls the operation of the power tool.

14. The power tool of claim 1 , wherein the PCBA is provided below the motor in the sealed compartment.

15. The power tool of either claim 1 , 2 or 3 wherein the PCBA includes a Motor Drive Controller (MDCB) to control operation of the motor, a Base Services Module (BSM) for data storage and communication and a User Interface Controller (UIC) to control operation of the power tool.

16. The power tool of claim 1, wherein the handle section couples with the sealed compartment in the housing section via sealed electrical terminals.

17. The power tool of claim 15, wherein when the handle section is coupled with the sealed compartment, the battery pack is mated with the MDCB and the BSM via the sealed electrical terminals establishing an electrical connection to power, the motor, the fan and the UIC.

18. The power tool of claim 1 , wherein the air passage is provided around the sealed compartment along the horizontal axis in the housing section, the air passage extends along the sealed compartment and terminates in the fan shroud.

19. The power tool of claim 1 , wherein the air passage is provided with an air intake and an air exhaust, the air exhaust is provided in the fan shroud.

20. The power tool of claim 19, wherein the fan is operated to suck ambient air into the air passage via the air intake and blow out from the air passage via the air exhaust.21 .The power tool of claim 20, wherein the flow of ambient air along the air passage facilitates in dissipating heat generated by the motor in the housing section.

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